Abstract:

A diffuser for a work machine having an air breathing fuel consuming
internal combustion engine with an exhaust aftertreatment device
periodically elevating the exhaust temperatures to a high level. The
diffuser has a venturi section and the excess contaminants from an intake
air pre-cleaner are directed to the throat of the venturi to aspirate and
dispose of excess contaminants while cooling the exhaust flow. Additional
openings in the divergent section of the diffuser assist in providing
significant reductions in exhaust temperatures within a short axial
envelope.

Claims:

1. An air pre-cleaner aspirator system for an air breathing fuel consuming
internal combustion engine having an air intake and an exhaust for the
products of combustion at elevated temperatures, said engine having a
pre-cleaner fluidly connected to and upstream of the engine air intake,
said pre-cleaner preventing flow of larger contaminants into the engine
air intake and accumulating such contaminants, said pre-cleaner having an
outlet for such contaminants, said system comprising:an element defining
a primary flow path for engine exhaust, said element having a venturi
section;a tube having an outlet within said element adjacent said venturi
section, said tube being fluidly connected to the pre-cleaner outlet for
contaminants so that contaminants are drawn into and through said tube;
andsaid element having at least one inlet for ambient air into the
primary flow path for cooling the engine exhaust stream adjacent said
element.

2. An air pre-cleaner aspirator system as claimed in claim 1, wherein said
element has a converging section, downstream throat and divergent section
connected to said throat, the outlet of said tube being at the upstream
portion of said throat.

3. An air pre-cleaner aspirator system as claimed in claim 2, wherein the
flow area at the upstream portion of said converging section is less than
the flow area at the downstream side of said divergent section.

4. An air pre-cleaner aspirator system as claimed in claim 1, wherein said
tube has a cross-sectional flow area sufficiently large to carry
contaminants into said primary flow path.

5. An air pre-cleaner aspirator system as claimed in claim 1, wherein said
primary flow path is defined by an annular wall and said wall has a
plurality of openings forming an inlet for ambient air for cooling up the
primary flow path adjacent said wall.

6. An air pre-cleaner aspirator system as claimed in claim 5, wherein the
walls of said element form a convergent, throat and divergent section,
said plurality of openings being positioned at the beginning of said
divergent section.

7. An air pre-cleaner aspirator system as claimed in claim 1, wherein said
tube enters said element at right angles to the primary flow path and the
outlet of said tube is in a direction substantially parallel to the flow
through said element.

8. An internal combustion engine system comprising:an air breathing, fuel
consuming internal combustion engine having an air intake and an exhaust
for products of combustion;an exhaust aftertreatment system generating
periodic significantly elevated temperatures;an air filtration system
including a pre-cleaner fluidly connected to and upstream of the engine
air intake, said pre-cleaner preventing flow of larger contaminants into
the engine air intake and accumulating such contaminants, said
pre-cleaner having an outlet for such contaminants;an element defining a
primary fluid flow path for engine exhaust from said exhaust
aftertreatment system, said element having a venturi section;a tube
having an outlet within said element and adjacent said venturi section,
said tube being fluidly connected to the pre-cleaner outlet for
contaminants so that contaminants and air are drawn into and through said
tube, to cool said exhaust; andsaid element having at least one inlet for
ambient air for further cooling the engine exhaust.

9. An internal combustion engine system as claimed in claim 8, wherein
said element defines a convergent section connected with a throat and a
divergent section, the outlet of said tube being positioned adjacent the
upstream portion of said throat.

10. An internal combustion engine system as claimed in claim 9, wherein
the cross-sectional flow area of the upstream portion of said convergent
section is smaller than the flow area of the downstream portion of said
divergent section.

11. An internal combustion engine system as claimed in claim 8, wherein
the cross-sectional flow area of said tube is sufficiently large to carry
contaminants to said primary flow path.

12. An internal combustion engine system as claimed in claim 8, wherein
said element has a wall defining said primary flow path, said openings
being positioned in the wall of said flow path for cooling the primary
flow path adjacent the walls of said element.

13. An air pre-cleaner aspirator as claimed in claim 12, wherein said wall
sections define an upstream converging section, a throat and a downstream
divergent section, said openings being positioned at the adjacent the
upstream portion of said divergent section.

14. An air pre-cleaner aspirator as claimed in claim 8, wherein said tube
enters said element at substantially a right angle to said primary flow
path, said tube being curved to have a discharge substantially parallel
to the primary flow path therethrough.

15. A work machine operating in a significantly contaminant laden
environment, said work machine comprising:a power train for propelling
and powering processing functions of said work machine;an internal
combustion engine system comprising:an air breathing, fuel consuming
internal combustion engine having an air intake and an exhaust for
products of combustion;an exhaust aftertreatment system generating
periodic significantly elevated temperatures;an air filtration system
including a pre-cleaner fluidly connected to and upstream of the engine
air intake, said pre-cleaner preventing flow of larger contaminants into
the engine air intake and accumulating such contaminants, said
pre-cleaner having an outlet for such contaminants;an element defining a
primary fluid flow path for engine exhaust from said exhaust
aftertreatment system, said element having a venturi section;a tube
having an outlet within said element and adjacent said venturi section,
said tube being fluidly connected to the pre-cleaner outlet for
contaminants so that contaminants and air are drawn into and through said
tube, to cool said exhaust; andsaid element having at least one inlet for
ambient air for further cooling the engine exhaust.

16. A work machine as claimed in claim 15, wherein said element has a
converging section, throat and downstream divergent section, the outlet
of said tube being adjacent the upstream portion of said throat.

17. A work machine as claimed in claim 16, wherein the cross-sectional
flow area of the upstream portion of said converging section is smaller
than the cross-sectional flow area of the downstream portion of said
divergent section.

18. A work machine as claimed in claim 15, wherein the cross-sectional
flow area of said tube is large enough to carry contaminants into said
primary flow path.

19. A work machine as claimed in claim 15, wherein said flow path through
said element is defined by wall sections, said element having a plurality
of openings forming said inlet for ambient air so that the flow path
adjacent the wall sections is cooled.

20. A work machine as claimed in claim 19, wherein said wall sections form
an upstream converging section, a throat and a downstream divergent
section, said openings being positioned adjacent the upstream portion of
said divergent section.

21. A work machine as claimed in claim 15, wherein said tube enters said
element at substantially a right angle to said primary flow path, said
tube being curved to have a discharge substantially parallel to the
primary flow path therethrough.

22. A compact exhaust cooling system for an air breathing fuel consuming
internal combustion engine having an air intake and an exhaust for the
products of combustion at elevated temperatures, said system
comprising:an element having an annular wall defining a primary flow path
for engine exhaust, said element having a venturi section;at least one
tube having an outlet within said element adjacent said venturi section,
said tube being fluidly connected to ambient so that cooling air is drawn
into and through said tube; andsaid element having at least one inlet for
ambient air into the primary flow path through said annular wall for
cooling the engine exhaust stream adjacent the wall of said element.

23. A work machine as claimed in claim 22, wherein said element has a
plurality of openings forming said inlet for ambient air so that the flow
path adjacent and around the wall sections is cooled.

24. A work machine as claimed in claim 23, wherein said wall forms an
upstream converging section, a throat and a downstream divergent section,
said openings being positioned adjacent the upstream portion of said
divergent section.

Description:

FIELD OF THE INVENTION

[0001]The invention relates to aspirators for air cleaning systems, and
more specifically, to aspirators used with internal combustion engines.

BACKGROUND OF THE INVENTION

[0002]The class of work machines utilized for agricultural, industrial and
other uses, termed as work machines, typically operates in a highly
contaminated environment, thus making the function of cleaning air used
by an air breathing internal combustion engine, especially important.
Nowhere is this as important as in the agricultural field where the work
machine is in a field harvesting crops which generates significant
contaminants in the form of chaff and dust. It is necessary for such
machines to have a pre-cleaner since the ambient level of contaminant is
so significant. A filter alone would quickly become clogged.

[0003]In the present environment, pre-cleaners are employed upstream of
the primary filter for the intake system of the engine. Such pre-cleaners
take various forms, but as used commercially, are systems that impart a
centrifugal motion to the air leading to the primary air filter inlet.
Such centrifugal motion causes the denser contaminants to be thrown to
the outer periphery of the pre-cleaner, leaving the less contaminated air
to exit to the primary filter through a central inlet. Such air
pre-cleaners have an outlet for the accumulated contaminants and some
units have that outlet connected to an aspirator positioned in a muffler
positioned in the engine exhaust system.

[0004]With the advent of environmental protection agency (EPA) emissions
regulations applying to off highway work machines, it is become necessary
to employ exhaust aftertreatment devices, including diesel particulate
filters. Such devices require periodic burning of the accumulated soot
particles to prevent clogging of the particulate filter. The process of
cleaning such particles, commonly referred to as regeneration, causes a
significant increase in the temperature of the exhaust, reaching levels
as high as 600° C. This elevated temperature represents a
potential problem in the contaminated environment of the work.

[0005]Accordingly, a need exists in the art to provide an effective and
compact way of cooling the engine exhaust, at the same time providing a
way of discarding contaminants collected in a pre-cleaner.

SUMMARY OF THE INVENTION

[0006]In one form, the invention is an air pre-cleaner aspirator system
for an air breathing, fuel consuming internal combustion engine having an
air intake and an exhaust for the products of combustion at elevated
temperatures. The engine has a pre-cleaner fluidly connected to and
upstream of the engine air intake, the pre-cleaner preventing flow of
larger contaminants into the engine air intake and accumulating such
contaminants. The pre-cleaner has an outlet for such contaminants. The
air pre-cleaner aspirator system includes an element defining a primary
flow path for engine exhaust, the element having a venturi section. A
tube has an outlet within the element adjacent the venturi section, the
tube being fluidly connected to the pre-cleaner outlet for contaminants
so that contaminants and ambient air are drawn into and through the tube.
The element has at least one inlet for ambient air into the primary flow
path for cooling the engine exhaust stream adjacent the element.

[0007]In another form the invention is an internal combustion engine
system having an air breathing, fuel consuming internal combustion engine
with an air intake and an exhaust for products of combustion. An exhaust
aftertreatment system receiving the products of combustion generates
periodic, significantly elevated temperatures. An air filtration system
including a pre-cleaner is fluidly connected to and upstream of the
engine air intake, the pre-cleaner preventing flow of larger contaminants
into the engine air intake and accumulates such contaminants, the
pre-cleaner having an outlet for such contaminants. An element defining a
primary fluid flow path for engine exhaust from said exhaust
aftertreatment system has a venturi section. A tube has an outlet within
the element and adjacent the venturi section, the two being fluidly
connected to the pre-cleaner outlet for contaminants so that contaminants
and ambient air are drawn into and through the tube to cool the exhaust.
The element has at least one inlet for ambient air for further cooling
the engine exhaust.

[0008]In another form, the invention is a work machine operating in a
significantly contaminant laden environment, the work machine having a
power train for propelling and powering processing functions of the work
machine. An air breathing, fuel consuming internal combustion engine has
an air intake and an exhaust for products of combustion. An exhaust
aftertreatment system receives exhaust from said engine and generates
periodic, significantly elevated temperatures. An air filtration system
includes a pre-cleaner fluidly connected to and upstream of the engine
air intake, the pre-cleaner preventing flow of larger contaminants into
the engine air intake and accumulating such contaminants. The pre-cleaner
has an outlet for such contaminants. An element defining a primary fluid
flow path receives engine exhaust from the exhaust aftertreatment system,
the element having a venturi section. A tube having an outlet within the
element and adjacent the venturi section is fluidly connected to the
pre-cleaner outlet for contaminants so that contaminants and ambient air
are drawn into and through the tube to cool the exhaust. The element has
at least one inlet for ambient air for further cooling the engine
exhaust.

[0009]In yet another form, the invention is a compact exhaust cooling
system for an air breathing fuel consuming internal combustion engine
having an air intake and an exhaust for the products of combustion at
elevated temperatures. The said system includes an element having an
annular wall defining a primary flow path for engine exhaust, the element
having a venturi section. At least one tube has an outlet within the
element adjacent the venturi section, the tube being fluidly connected to
ambient so that cooling air is drawn into and through the tube. The
element has at least one inlet for ambient air into the primary flow path
through the annular wall for cooling the engine exhaust stream adjacent
the wall of the element.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a schematic view of a work machine in which the present
invention is employed; and

[0011]FIG. 2 is a side view of an air pre-cleaner aspirator incorporated
in the schematic of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

[0012]Referring to FIG. 1, there is shown a portion of a work machine 10
in the form of an agricultural vehicle, particularly the rear end drive
train of the vehicle. Although shown as an agricultural vehicle it is
possible the work machine 10 could be in the form of a different type of
work machine such as a construction or forestry vehicle.

[0013]Work machine 10 includes a transmission 12 providing motive power to
the work machine 10 as well as power agriculture crop harvesting and
processing components as well as various hydraulic accessory devices.
Transmission 12 is powered by an air breathing fuel consuming internal
combustion engine, generally shown at 14. Internal combustion engine 14
exhausts the products of combustion to an exhaust line 16 extending to a
turbine 18 which drives a compressor 20 through a mechanical
interconnection 22. The exhaust from turbine 18 passes through line 24 to
an exhaust aftertreatment device 26.

[0014]Exhaust aftertreatment device 26 may incorporate a number of
elements that usually include an oxidization catalyst and a particulate
filter, both of which are not shown to simplify the understanding of the
invention. The particulate filter discharges gases through a line 28 to a
diffuser 30 to be described below and finally to an outlet line 32 where
it is exhausted to ambient. The particulate filter within device 26
requires periodic regeneration of accumulated carbon particles on the
filter by elevating the upstream temperature to around 300° C.
This causes the soot particles within the filter to burn thus increasing
the exhaust temperature up to around 600° C. which requires
management by the diffuser 30 to bring temperatures within acceptable
limits.

[0015]Ambient air passes by inlet line 34 through a pre-cleaner 36 and
line 38 to a primary air filter 40. The outlet 42 of primary air filter
40 passes to the compressor 20 and from there through a line 44, usually
through an aftercooler or intercooler 46 to intake 48 for the internal
combustion engine 14.

[0016]The work machine 10 has two sets of material required to be disposed
of. First is material from the pre-cleaner 36. Pre-cleaner 36 usually
involves some form of device imparting a centrifugal flow to the air
passing from inlet 34 so that the heavier particles are spun to a
periphery and have and are collected in an outlet line 50. Pre-cleaner
devices of this type are commercially available through a number of
companies. At the same time the material from the debris and excess
contaminants needs to be disposed of from line 50, the air from
downstream of the particulate filter in line 28 is required to be cooled.
In accordance with the present invention, the diffuser shown in detail in
FIG. 2 is employed.

[0017]The diffuser, generally indicated by reference character 30, has an
inlet end 54 connected to line 28 from the aftertreatment device 26 and
an outlet 56 connected to exhaust line 32 leading to ambient. The inlet
of diffuser 52 has an initial inlet section 58 leading to a convergent
annular section 60, a throat 62, divergent section 64 and outlet section
66 to form a venturi. As illustrated, the various sections are annular in
cross-section although some variation from annular may be employed. It
should be noted that the cross-sectional flow area of inlet section 58
leading to convergent section 60 is smaller than the flow area of the
downstream and of divergent section 64 as it intersects outlet section
66. A pipe 68 extends through the wall of inlet section 58 and curves
through 90° to an outlet 70 positioned approximately adjacent the
upstream end of the throat 62. Pipe 68 is connected to line 50 leading
from the pre-cleaner 36 and extends into the diffuser at a right angle to
the longitudinal axis of the diffuser 30 and curves to have an outlet
parallel to the primary airflow through diffuser 30. The cross-sectional
flow area of tube 68 is sufficiently large to pass expected contaminant
particle sizes along with ambient air.

[0018]At least one, and preferably a plurality of openings 72, are
provided adjacent the upstream end of divergent section 64. Openings 72
provide and allow passage of air from the ambient into the interior of
diffuser section 64.

[0019]In operation, the internal combustion engine 14 requires a flow of
inlet air which passes through pre-cleaner 36 as the work machine 10
travels through highly contaminated environments such as harvesting crops
in the field, excess debris passes into the pre-cleaner 36 where it is
centrifugally directed to be collected by line 50. As the exhaust flow
passes from the exhaust aftertreatment device 26, the air passing by the
outlet 70 of tube 68 causes a drop in pressure which in turn draws air
from line 50 by aspiration through pipe 68 and out of outlet 70 where it
is mixed with exhaust flow. In addition to disposing of the excess
contaminants, the ambient flow from the pre-cleaner 36 causes a reduction
in temperature in the flow from line 28 particularly with the exhaust
aftertreatment devices being regenerated. The openings 72, provided at
the upstream portion of divergent section 64, provide additional flow of
ambient air to cool the walls of the diffuser section to thereby provide
a synergy where the flow from the pre-cleaner cools the core of the flow
through the diffuser 52 and the air from the opening 72 provide cooling
of the walls. Accordingly, the diffuser 52 not only provides disposal of
the excess contaminants from the pre-cleaner but it cools the exhaust
flow directed through outlet 32 to a manageable level for the operating
environment of the work machine. It should be noted that the dual cooling
function enables significant temperature reductions within a relatively
short axial envelope and can be used to cool the exhaust flow independent
of an aspirating function.

[0020]Having described the preferred embodiment, it will become apparent
that various modifications can be made without departing from the scope
of the invention as defined in the accompanying claims.